本来想修改一下数据库登陆密码：
mysql> update user set password=password(“新密码”) where user=”用户名”;
执行后报错 ERROR 1054(42S22) Unknown column 'password' in ‘field list’
错误的原因是 5.7版本下的mysql数据库下已经没有password这个字段了，password字段改成了authentication_string
修改密码：
mysql> use mysql;
Database changed
mysql> select User from user; #此处为查询用户命令
+-----------+
| User |
+-----------+
| ******* |
| mysql.sys |
| root |
+-----------+
3 rows in set (0.00 sec)
mysql> update user set password=password("*******") where user="*******"; #修改密码报错
ERROR 1054 (42S22): Unknown column 'password' in 'field list'
mysql> update mysql.user set authentication_string=password('*******') where user='*******'; #修改密码成功
Query OK, 1 row affected, 1 warning (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 1
mysql> flush privileges; #立即生效
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Bye
n>mysql -u ******* -p #以该用户登录成功.
Enter password: ********
…………………………
mysql>